Plethysmograph pulse recognition processor

Abstract

A time domain rule-based processor provides recognition of individual pulses in a pulse oximeter-derived waveform.

1. A patient monitor comprising:
 an input which receives a sensor signal indicative of light attenuated by body tissue; and 
 a processor which applies a plurality of first edge analysis rules to identify potential pulses from within said sensor signal or from within signals derived from said sensor signal, the processor also applying a plurality of second pulse feature rules to identify acceptable pulses from within said potential pulses, wherein said plurality of said second rules comprise at least one signal modeling rule. 
 
     
     
       2. The monitor of  claim 1 , wherein the processor determines statistical pulse rate information from said acceptable pulses. 
     
     
       3. The monitor of  claim 2 , wherein said statistical pulse rate information comprises pulse period information. 
     
     
       4. The monitor of  claim 2 , wherein said statistical pulse rate information comprises pulse density information. 
     
     
       5. The monitor of  claim 1 , wherein said at least one signal modeling rule determines a difference between at least one signal model and said potential pulses. 
     
     
       6. The monitor of  claim 5 , wherein where said at least one signal modeling rule varies acceptable threshold values to be compared to said difference. 
     
     
       7. The monitor of  claim 6 , wherein said varying is pulse dependent. 
     
     
       8. The monitor of  claim 7 , wherein signal features of said potential pulses change when said pulse changes. 
     
     
       9. The monitor of  claim 6 , wherein said varying accounts for effects of a rising pulse rate on said potential pulses. 
     
     
       10. The monitor of  claim 1 , wherein the pulse feature rules relate to a pulse starting point. 
     
     
       11. The monitor of  claim 1 , wherein the pulse feature rules relate to a period. 
     
     
       12. The monitor of  claim 1 , wherein the pulse feature rules relate to a signal strength.